A multidisciplinary study of the structural, biochemical and functional properties of human skin during development is planned. Samples of normal embryonic and fetal skin will be used to establish histologic and ultrastructural characteristics of the epidermis, dermis and amniotic fluid cell populations at progressive stages of development. These data will serve as the common denominator of all other projects; parallel samples of skin from the same embryos and fetuses used for the morphologic studies will be used for: quantitation of hemidesmosomes at the dermal-epidermal junction, biochemical assay and immunolocalization of the epidermal proteins filaggrin and keratin, biochemical identification of specific classes of lipids in the epidermis, subcutaneous fat and amniotic fluid, evaluation of transport across the epidermis, biochemical identification and immunolocalization of the major interstitial collagens in the dermis, and identification and quantitation of dermal glycosaminoglycans, evaluation of synthesis and activity of dermal collagenase, at various stage of development. Biopsy and autopsy samples of skin from fetuses with inherited cutaneous disorders will also be studied for morphologic alterations and by as many of the biochemical procedures our tissue quantity allows. The data from these projects are expected to expand our understanding of normal human skin biology during development, serve as control, baseline data essential for evaluation of abnormalities in cutaneous structure and properties in fetuses at risk for severe inherited disorders of the integument, expand tee potential for prenatal diagnosis of skin disorders and extend our understanding of the natural history of genetic skin diseases into the antenatal period.